Strengthening integrated depression services within routine primary health care using the RE-AIM framework in South Africa

Integration of mental health into routine primary health care (PHC) services in low-and middle-income countries is globally accepted to improve health outcomes of other conditions and narrow the mental health treatment gap. Yet implementation remains a challenge. The aim of this study was to identify implementation strategies that improve implementation outcomes of an evidence-based depression care collaborative implementation model integrated with routine PHC clinic services in South Africa. An iterative, quasi-experimental, observational implementation research design, incorporating the Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) framework, was applied to evaluate implementation outcomes of a strengthened package of implementation strategies (stage two) compared with an initial evaluation of the model (stage one). The first stage package was implemented and evaluated in 10 PHC clinics and the second stage strengthened package in 19 PHC clinics (inclusive of the initial 10 clinics) in one resource-scarce district in the province of KwaZulu-Natal, South Africa. Diagnosed service users were more likely to be referred for counselling treatment in the second stage compared with stage one (OR 23.15, SE = 18.03, z = 4.04, 95%CI [5.03–106.49], p < .001). Training in and use of a validated, mandated mental health screening tool, including on-site educational outreach and technical support visits, was an important promoter of nurse-level diagnosis rates (OR 3.75, 95% CI [1.19, 11.80], p = 0.02). Nurses who perceived the integrated care model as acceptable were also more likely to successfully diagnose patients (OR 2.57, 95% CI [1.03–6.40], p = 0.043). Consistent availability of a clinic counsellor was associated with a greater probability of referral (OR 5.9, 95%CI [1.29–27.75], p = 0.022). Treatment uptake among referred service users remained a concern across both stages, with inconsistent co-located counselling services associated with poor uptake. The importance of implementation research for strengthening implementation strategies along the cascade of care for integrating depression care within routine PHC services is highlighted.


Introduction
Low-and middle-income countries (LMICs) face a crisis as the high existing toll of communicable diseases meets the rapidly growing burden of non-communicable diseases (NCDs) [1].This crisis is coupled with a large untreated burden of depression-an estimated 92% of people with depression do not receive treatment [2], with depressive disorders being the most prevalent health condition in sub-Saharan Africa [3].Depression co-existing with chronic medical conditions is associated with poorer health outcomes and increased mortality [4,5].The World Health Organization (WHO) has advocated for integration of treatment for mental health conditions into primary health care (PHC) for decades.In addition to providing a viable approach for narrowing the treatment gap, this approach provides a platform for the treatment of co-existing mental and medical conditions simultaneously, improving outcomes for both [6].The Mental Health Gap Action Programme (mhGAP), initiated in 2008, offers training, evidence-based guidelines, and tools for assessment and integrated management of mental health conditions by non-specialist PHC practitioners using a task-sharing approach [7].The collaborative care model has demonstrated strong effectiveness in treating people with mental and physical multi-morbidities, though most of this evidence comes from controlled trials in high-and middle-income countries [8][9][10].There is little evidence on best practices for integrated collaborative depression care for people with chronic medical conditions, within routine PHC services, from lower-resource contexts globally [11][12][13].This study used implementation science to help narrow this evidence gap in one LMIC country-South Africa.
South Africa provided an opportune country setting to test and understand best practices to implement integrated depression care into routine PHC services for people with chronic conditions for the following reasons.It has a PHC system uniquely burdened by high rates of HIV and TB coupled with rapidly growing rates of NCDs [14], alongside a high burden of undetected co-existing mental health conditions [15,16].Against this epidemiological backdrop, health systems reforms aimed at strengthening integrated care for people with chronic conditions at the PHC level provided an enabling policy environment [17,18].
The aim of this study was to use implementation research methods to strengthen and evaluate a package of implementation strategies to optimise real-world delivery of an evidencebased integrated collaborative depression care model for PHC services in South Africa tested in a cluster randomized trial elsewhere [19].This original model strengthened nurse clinician assessment, diagnosis and management of comorbid depression in chronic care PHC patients, inclusive of strengthened referral pathways for medical and psychological treatment.The study formed part of the Southern African Research Consortium for Mental health INTegration (S-MhINT).

Study site
The study site was the Amajuba District of the KwaZulu-Natal (KZN) province on the eastern seaboard of South Africa.The district is home to approximately 500 000 people and comprises three sub-districts covering urban, peri-urban and rural areas.It thus provided the opportunity to examine implementation of the collaborative care package across diverse settings.The evidence-based model was initially implemented in 13 fixed-PHC clinics in one urban sub-district, with fixed-clinics comprising infrastructure located in one geographic area.Informed by findings from an evaluation of this initial implementation, the implementation strategy package was then strengthened and expanded to all fixed-PHC clinics across the three sub-districts of Amajuba (n = 24), inclusive of the initial clinics where it was implemented.All PHC clinics were serviced by Professional Nurses who have a three/four-year diploma/degree in nursing, Enrolled Nurses who have a two-year diploma, sessional PHC doctors who visit for one session per week, and HIV counsellors funded by the Department of Health (DoH) using a conditional grant from the United States President's Emergency Plan for AIDS Relief (PEPFAR).Across the study period (2018-2022), mental health specialist referral services provided by the DoH comprised between one to three clinical psychologists who offered psychological services at two district hospitals.

Study design
The study adopted a two-stage, iterative, quasi-experimental, observational mixed methods implementation research design [20], reported in detail in the research protocol [21] (See Fig 1).We used the same study procedures in both stages to minimise bias.In both stages, implementation outcomes were evaluated at the service user, provider, and organizational levels using the RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) framework [22,23].RE-AIM has been widely used to assess the population health impact of interventions in real-world settings.

RE-AIM data collection and analysis
Data measures and collection procedures.To assess RE-AIM outcomes across both stages, we used project data sources, including facility profiles and implementation records, data collected through two patient cohorts, one in stage one and another in stage two; as well as two rounds of a cross-sectional provider survey, also one in each stage.Although all study participants were de-identified using study identification numbers, the Principal Investigator and data manager had access to separately held implementation records containing information with personal identifiers of individual participants during and after data collection to facilitate follow-up of cohort participants, link participants in terms of counselling uptake, and maintain training records to link to provider characteristics and outcomes.Identifying details were deleted once linked.The cohort studies and nurse cross-sectional surveys were conducted in 2018 in 10 of the 13 facilities in the urban sub-district in the first stage; and in the secondstage were conducted in 2022 in 19 of the 24 facilities across the urban, semi-rural and rural districts (inclusive of the original 10 clinics in the urban sub-district).Missing data on key variables from each stage of data collection was dropped for the purpose of analysis.Less than 2% of data in each stage was missing.Non-participation occurred if the nurse was off-duty or on night shift at the time of the data collection.Strengthening of the intervention occurred from 2019-2021, with delays incurred due to the COVID-19 pandemic.
Reach was assessed along the cascade of care at the facility level at both stages.We used cohort baseline data from 412 participants from stage one, and 633 participants from stage two, who screened positive for depressive symptoms by our fieldworkers prior to assessment by a nurse.We assessed the proportion and characteristics of participants in these cohorts who were subsequently diagnosed, referred to care, and who took up the co-located counselling services provide by trained and supervised existing HIV clinic-based counsellors.The study samples in both stages were powered based on the cohort design [24].Nurses were asked to complete a checklist indicating whether they had made a depression diagnosis and a referral to a counsellor in both stages.Participants in the first stage were restricted to adult service users with an existing physical chronic illness.At the request of the DoH, participants in the second stage included all adult PHC service users attending chronic and acute services.We linked research participants referred for counselling to independent project data on counselling attendance records in both stages.This was done manually using clinic and participant name, both of which were collected by the two independent data bases.Generalized linear mixedeffects models were used to estimate associations between patient and facility characteristics and service delivery outcomes along the cascade of care.To compare reach along the cascade of care between the two stages, logistic regression was used to estimate the difference in overall rates of diagnosis, referral and uptake, adjusting for facility clustering and the same covariates used in the stage-specific analyses.
Effectiveness was measured in the first stage in terms of associations between PHC nurse diagnosis and referral for depression management and subsequent patient-level depression outcomes using the patient cohort.Cohort participants were identified by screening primary care attendees at the participating PHC facilities for depression symptoms using the Patient Health Questionnaire-9 (PHQ-9) by research assistants.Participants scoring �9,-the locally validated cut-off for the chronic patient population [25]-were offered enrolment and followed up at 3-and 9-months post-enrolment in the first stage evaluation.In the second stage, because of delays associated with the COVID-19 pandemic, participants were only followed up at 3-months post-enrolment.In the first stage, a 50% reduction in PHQ-9 raw scores from baseline to 3-and 9-months follow-up were compared across three groups-cohort patients screened positive for depression by our research fieldworkers who were not diagnosed; patients diagnosed with depression but who were not referred for treatment; and patients diagnosed and referred for treatment-while adjusting for baseline PHQ-9 scores and other characteristics using multivariable models [24].These three groups were identified using the nurse checklist used for the Reach data, where they indicated whether they had made a depression diagnosis and a referral to a counsellor.
Adoption focused on assessing and understanding variation in the Reach care cascade at an individual and facility level.In relation to variation in referral and counselling uptake across facilities in the first stage, we used a generalized linear mixed effects model to estimate the association between the availability of a facility counsellor during the cohort implementation period and the proportion of referred service users successfully receiving at least one counselling session at each facility.Facility-specific counts of service users referred for counselling over the implementation period were used as frequency weights.The model included a random facility-specific intercept and used the binomial family and logit link.In the second stage, we applied logistic regression analysis to the baseline cohort data linked with project counselling attendance data and counsellor availability to assess variations in facility rate of referral and counselling uptake of service users screening positive for depression.To understand characteristics of nurse providers with high and low referral rates, we administered a cross-sectional survey during the first and second stage cohort studies to the full complement of available Nurse Clinicians servicing the facilities in the first (N = 68) and second stages (N = 136).These data were linked with nurse self-reported referrals on the nurse checklist that was used to identify high and low referring nurses, determined by whether nurses reported 100% of screen positive patients referred vs. less than 100%.At the time of the study, nurse clinicians in South Africa were not mandated to provide anti-depressant treatment and did not have the time or capacity to provide counselling.Unlike in other contexts, referral presented the only avenue for accessing treatment for patients diagnosed with depression.The quality metric of 100% for referral was thus used given this context.
The survey included the following scales previously administered in South Africa: Organizational Readiness for Implementing Change (ORIC), the MICA Mental Illness: Clinicians' Attitudes Scale (MICA), Role Overload Scale and Intervention Acceptability (AIM) (See Kemp, Mntambo et al. 2021 for further details) [26] in both stages.The General Health Questionnaire (GHQ) was added to assess provider physical and mental health status in the second stage.Project records on screening outreach training as well as online nurse training records were also linked to the nurse survey data in the second stage.We applied logistic regression to determine predictors of nurse variation in diagnosis and referral.
For Implementation, we assessed whether consistency of facility-counsellor presence was associated with counselling referrals and counselling uptake.We used project record data for January to December 2018 and January to September 2022.Referral rates were extracted from referral forms and patient counselling uptake was assessed using patient tracking forms.Consistency of lay-counsellor presence was assessed using facility profiles.Nurse checklist data on referrals from the cohort study were linked with project record data on counselling uptake via patient names as well as counsellor presenteeism from facility profiles during the cohort study period.In the first stage, we used a generalized linear mixed effects regression model to estimate the association between the availability of a facility counsellor throughout the implementation period and the proportion of referred service users successfully receiving at least one counselling session at each facility.In the second stage, we added consistency of lay counsellor presence to the baseline cohort data and used generalized linear mixed-effects models to estimate associations between patient counselling uptake and counsellor presenteeism.
We assessed counselling fidelity using a bespoke counselling fidelity rating checklist adapted from ENACT and previously used as part of the evaluation of the original package [27].
For Maintenance, at the individual level, we followed up service users in the first stage cohort study at 9 months to establish stability of effects on depression symptom reduction over time.At the organizational level, we reviewed minutes of provincial meetings with policy makers from the Mental Health Directorate of the KZN DoH as well as meetings held with national policy makers to assess uptake of innovations from the SMhINT implementation package into policy.
Ethical considerations.Fieldworkers verbally explained the rationale for the study to potential participants.Once verbal consent was given, the study details were explained, and questions from the potential participants were addressed.The voluntary nature of participation was reiterated, and willing participants provided informed signed consent.Participants were given a copy of the information document for their records.The study was performed in accordance with the ethical standards contained in the 1964 Declaration of Helsinki.Ethical approval was obtained from the Biomedical Research Ethics Committee at the University of KwaZulu-Natal (BF190/17) and the Directorate of Health Research and Knowledge Management in KwaZulu-Natal (HRKM253/17 KZ_2017RP15_388) in the KwaZulu-Natal Department of Health.

Description of the implementation package and how the results of the first stage evaluation informed the strengthening of the implementation strategies in the second stage
The initial and strengthened packages of implementation strategies were layered onto existing activities for other conditions within PHC facilities and included several strategies from the Expert Recommendations for Implementing Change (ERIC) compilation [28] (italicised below).The initial package aimed to i) Orientate and optimize buy-in and support from district and PHC clinic managers through orientation workshops (educational meetings and preparing champions); ii) Improve demand through training (educational meetings) of existing staff to provide psychoeducational material on depressive symptoms in the waiting room area so as to strengthen mental health literacy; iii) Improve nurse clinician assessment and diagnosis of depressive symptoms through the provision of additional mental health training (using a train the trainer approach) in the use of an existing national evidence-based clinical decision support tool aligned with mhGAP called Adult Primary Care (APC)-also known internationally as the Practical Approach to Care Kit (PACK) [29]; iv) Strengthen referral pathways through training (educational meetings) and supervision of existing facility-based HIV counsellors in a manualized lay-counselling intervention (educational materials) that drew on cognitive behavioral techniques and problem solving, both shown to be effectively delivered using a task sharing approach [30].This implementation strategy package complemented existing mental health services that included i) Screening provided in the vital signs room, although there was no standardized, validated screening tool in use, with PHC clinics adopting a variety of tools made up of screening items from various instruments; ii) Existing referral pathways for people with more severe depressive symptoms to the sessional PHC doctors to whom initiation of antidepressant medication was restricted, or to mental health specialists at the district level.Project-supported technical support using cyclical small tests of change was used to embed the different components within the system, using routine mental health indicators of number screened and number treated.The first stage package is outlined in Table 1, with more details available in previous publications [21,31].
Evaluation of implementation outcomes and determinants of the initial stage one package using the RE-AIM framework are reported in previous publications [24,26,32], summarized in Box 1, and outlined in Table 2.

Strengthening of the implementation strategy package in response to the findings of the first stage evaluation
Findings from the first stage evaluation were shared as they emerged and implementation was purposely re-examined collectively through local consensus discussions to address the challenges identified to tailor implementation strategies, mandate changes at a policy level including tools,  [26].Participants more likely to be diagnosed with depression by nurses reported greater symptom severity, suicidal thoughts, perceived stress, disability and high risk/dependent alcohol use details.
Participants more likely to be referred had fewer chronic conditions, with the exclusion of HIV; and participants in receipt of at least once counselling session were more likely to have less social support [26].
Effectiveness: As reported in Kathree et al. [24], participants diagnosed and referred had lower PHQ-9 scores at three months, and were more likely to have their PHQ-9 scores decreased by more than 50% from baseline to three months follow-up compared to participants diagnosed and not referred [23].Outcomes did not differ significantly between the groups at nine months follow-up, similar to what was found in a previous evaluation of the same counselling intervention under controlled conditions [33].As suggested by Kathree et al. [24] this is likely to be a result of spontaneous remission, especially within the mild to moderate cases which were dominant in the sample, and where people with mild to moderate symptoms more likely to spontaneously remit [34].
Adoption: At the individual level, project record data over a period of three months during 2018 (June-August 2018) revealed that Professional Nurses referred on average 1.2 service users per month, with median referral rates per month ranging from 0 to 2.75 [26].Poor referral was attributed to lack of perceived competency-whereby the pre-COVID cascade model of APC training using a train the trainer strategy (whereby master trainers are equipped to train facility trainers who in turn train clinic staff) impacted negatively on implementation fidelity; unattended personal emotional issues of staff; low demand for counselling on the part of service users; and the need for mandating of a standardized and valid routine mental health screening tool [26].
record systems and roles of healthcare providers.This process also responded to additional mental health issues emerging during the COVID-19 pandemic.
The second stage package is also outlined in Table 1, with more details provided in online supplements using the Template for Intervention Description and Replication (TIDieR) checklist [35].The extended TIDieR prompts researchers to describe the intervention as well as specify implementation strategies [36].Similar to Proctor et al. guidance [37], the checklist includes specification of who provided each strategy (who enacted), how (actions/activities to support implementation), to whom (action target/entity impacted), and when and how much (temporality and dose) [35].
The challenges and changes are summarized below and outlined in Table 1:

i. Poor demand for mental health services by service users
The educational material and education workshops for providers of waiting room talks were expanded beyond just depressive symptoms, to include anxiety and grief and bereavement, particularly related to COVID-19.Greater emphasis was placed on capacitating service users with skills to cope with life stressors, beyond healthy lifestyle information included in the first stage.To this end, links to digitalized educational materials using cognitive behavioural, problem solving and mindfulness skills-building animated videos were provided as well as toll-free counselling hotline telephone numbers.Educational materials were distributed across all facilities in the district (See more details in TIDieR description in the online Supporting Information, S1 Appendix) ii Half of the clinics in the first stage had a counsellor available over the entire implementation period.Among clinics without a counsellor available over the entire implementation period, 16% (95%CI [1%-30%]) of referred service users received at least one session of counselling.Among facilities with a counsellor available over the entire implementation period, 57% (95%CI [34%-81%]) received at least one session of counselling.Uptake of the co-located counselling service was compromised by lack of availability of lay counsellors, with availability of a counsellor over the entire implementation period associated with a 42% relative increase in the probability of referred service users receiving at least one counselling session 95%CI [14%-69%].
Fidelity ratings by the counsellor supervisor using a bespoke fidelity counselling rating scale in the first stage were high across the facilities, ranging from 78 to 98%, with an average of 86%.iii.Train the trainer approach to capacitate Professional Nurses in the APC mental health guidelines and nurse healthcare worker emotional burden limited perceived competency and willingness to diagnose and refer depression in service users With the start of the COVID-19 pandemic, APC training was moved to a digital platform instead of an in-person, train-the-trainer approach.Digitalized educational material was developed and distributed to all Professional Nurses (with no mobile data-related costs to users).The role of the clinic facility trainer was re-configured to provide technical assistance for uptake of self-directed education.This was because more than 80% of the nurses had no experience of online training, and required assistance with registration on the platform [39].Shifting to digital training ensured fidelity of delivered training material and facilitated tracking of training coverage in each facility.These data were fed back to each facility to improve training coverage (audit and feedback).In addition, digitalized wellness educational material was developed for PHC nurses to support coping with the stressors imposed by COVID-19 and the emotional labour accompanying assessment, diagnosis and management of people with mental health conditions.(See more details in TIDieR descriptions in the online Supporting Information, S3 and S4 Appendices iv.Depression counselling not part of the role and functions of existing HIV counsellors leading to variable availability of the counselling service HIV counsellors who were being trained by the KZN DoH to become social auxiliary workers were targeted for training to improve role consonance (revise credentialing and roles) with their job description (See more details in TIDieR description in the online Supporting Information, S5 Appendix

Results
Stage two RE-AIM outcomes are summarised and compared against stage one outcomes in Table 2.

Reach
In the second stage, a sample of 1274 participants consented to be screened for depressive symptoms and participate in the cohort study, with a 3% refusal rate.Of the sub-sample of 633 stage two cohort participants who screened positive for depressive symptoms prior to assessment by a nurse, 48.3% were diagnosed with depression by nurses (N = 306/633).Of these, 91.2% were referred (N = 279/306) translating into 44.1% (N = 279/633) of the cohort subsample that screened positive for depressive symptoms at baseline being referred for counselling.However, of those referred, only 17.8% received at least one counselling session (N = 50/ 279), translating into 7.9% of the original sub-sample of service users screening positive for depressive symptoms (N = 50/633).(Table 2) Participants who were more likely to be diagnosed with depression by nurses were more likely to report greater symptom severity (OR 1.07 95%[CI 1.00-1.15],p = 0.048), suicidal thoughts (OR 1.69 95%[CI 1.04-2.76]p = 0.035), perceived stress (OR 1.08 95%[CI 1.03-1.12]p = 0.001), and high risk/dependent alcohol use (OR 1.12 95%[CI 1.01-1.23]p = 0.035), similar to the first stage.Unlike the first stage, most of the diagnosed service users were also referred (91.2%), so it was not possible to identify patient-level characteristics associated with referral in the second stage.Patient participants receiving at least once counselling session were less likely to have completed high school compared to those that had (OR 0.24 95% [CI 0.07-0.79]p = 0.02).(See Tables 3 and 4).
Comparative analysis of reach along the cascade of care across both stages was conducted using logistic regression.The logistic regression showed an odds ratio of 21 and 23 (unadjusted and adjusted for covariates, respectively) (OR 23.15, SE = 18.03, z = 4.04, 95%CI [5.03-106.49]p < .001).There was no statistically significant difference in the odds of diagnosis and uptake (Fig 2).

Effectiveness
Given that almost all of the participants who were diagnosed were also referred in the second stage, there were insufficient numbers of patients in the diagnosed and not referred group to conduct an analysis comparing participant PHQ-9 outcomes between diagnosed and not referred and diagnosed and referred groups, as in stage one.

Adoption
With regard to adoption by Professional Nurses, project record data over a period of four months during 2022 (Jan-April 2022) revealed that Professional Nurses referred on average of two service users per month (median: 1.5), with median referral rates per month ranging from 0.5 to 8.5.Most nurse providers making a diagnosis also made a referral (91.5%), with diagnosing nurse providers more likely to have received training in screening using the BMH (OR 3.75, 95% CI [1.19, 11.80], p = 0.02).Diagnosing nurse providers were also more to perceive the intervention as acceptable (OR 2.57, 95% CI [1.03-6.40],p = 0.043).(See Tables 5 and 6).

Implementation
Two-thirds (68.4%) of cohort clinics had a clinic counsellor consistently available over the cohort period.Consistent availability of a clinic counsellor was associated with a greater probability of being referred (OR 5.9, 95%CI [1.29-27.75],p = 0.022) (See Table 4).

Maintenance
Organizationally, several elements of the package have been adopted for scale up by the DOH in South Africa.The facility-based psychoeducational material was scaled up to all districts in KZN province by the KZN DoH during the COVID 19 pandemic (see www.crh.ukzn.ac.za).
The KZN DoH also accepted the BMH screening tool as the standardized mental health screening tool to be used in PHC facilities, and training was conducted with the district mental health coordinators and district trainers to implement and train facility staff in the tool across the province (www.crh.ukzn.ac.za).The APC integrated clinical decision support tool and self-directed online 30 session APC training with additional mental health modules is available nationally (https://knowledgehub.health.gov.za/course/adult-primary-care-2020-update),together with the Wellness Resource, although the latter has not been formally adopted by the DoH.The task sharing of the facility-based counselling service has also not been formally adopted as of now.

Discussion
Using RE-AIM as a guiding framework, this study has yielded several important lessons for optimizing implementation and uptake of integrated depression care within routine PHC clinic services.Regarding Reach at the PHC facility level, there was no significant change across the two stages in the percentage of PHC service users identified as having depression (roughly half) by nurse providers of those who screened above the established cut-off of �9 on the PHQ-9.This finding aligns with international findings of accurate detection of depression at PHC level [40].Service users with more severe symptoms, suicidal thoughts, and perceived stress were more likely to be diagnosed with depression across both stages.Given scarce mental health professionals, these findings suggest that nurses in both stages were proficient at identifying service users most in need of treatment, based on symptom severity.A key finding was that the probability of referral was substantially higher in the second stage (over 90%), compared to the first stage (37%).
Regarding adoption, findings from the linked cross-sectional nurse survey in the second stage indicated nurses who found the integrated package acceptable as well as those in receipt of outreach training and technical support in the validated and mandated BMH screening tool were more likely to make a diagnosis, with most diagnosed patient participants also referred.A recent review suggests uncertainty about whether screening for depressive symptoms improves mental health outcomes as a result of better identification and treatment of people with depression who would otherwise have gone unrecognised [41].As an adjunct tool to APC diagnostic treatment algorithms in PHC in South Africa, our results suggest that training and support in the use of standardized validated screening tools helps to alert nurses of the possibility of depression and the need to assess for possible diagnosis.In relation to implementation, counsellor availability and greater role consonance with their training to become social auxiliary workers also impacted on diagnosis and referral.The lay counselling service was more consistently available and acceptable within the facilities in the second stage.This was due to the transitioning of HIV counsellors to social auxiliary workers, with limited mental health services part of their scope of practice.This addressed the problem of mental health counselling not previously being part of the scope of work of HIV counsellors, with their scope of practice restricted to pre-and post-test HIV and adherence counselling [42].While more available and accepted in the facilities, the counsellors were, however, not always immediately present to receive a referral on the day of the referral as they were completing their training to become social auxiliary workers.This may have accounted for the lack of improvement in counselling uptake of referrals between the two stages.Referral for counselling was shown to be beneficial for service users with depression in the first stage evaluation [24], and thus a viable alternative to specialist counselling services in resource scarce settings.
Previous research suggests immediate linkage to counselling is important to promote counselling uptake [43].Contextual factors may also have compounded service users' capacity to attend clinics for counselling sessions.Off-site collection/distribution of medication was significantly expanded during the COVID 19 pandemic [44], and has since been maintained, reducing the number of PHC clinic visits by service users.The need for strengthening of community level mental health services is highlighted.To this end, through a SMhINT supplementary grant, a Community Mental Health Education and Detection (CMED) tool was cocreated with the KZN DoH following the second stage.This tool uses vignettes and a prototype matching approach to assist community health works (CHWs) to provide mental health education, screening and linkage to care in their routine household visits [45][46][47].The need for future research to evaluate its role in increasing demand and uptake of mental health and social services is indicated.CHWs are well placed to link community members to both health and social interventions where indicated; this being important given the well-established social determinants of poor mental health [38,39].
In pursuit of narrowing the care gap for depression, the importance of whole systems strengthening along the PHC care cascade is underscored.While the percentage of screen positive service user participants who received the co-located counselling service was still very low in the second stage (8% of the original sample who screened positive for depressive symptoms using the PHQ9), it was far higher than the percentage of service users suspected of having a CMD based on national prevalence rates [48] initiated on treatment by limited PHC doctors/specialists using routine data for the district, estimated to be 0.19% [49].Given that the efficacy of lay counselling services under controlled trial conditions is now well-established in LMICs, including South Africa [19,30,50], our study highlights the potential of task sharing of co-located counselling services in PHC for helping to narrow the care gap for depression, estimated to be as high as 97% in LMICs [2].The need to mandate a health worker cadre to provide this service under supervision has been previously highlighted [43].Further, given the shortage of primary health care doctors outside of the metropolitan areas of South Africa [51], the need for legislative and regulatory changes to enable nurses, who form the backbone of the PHC system in South Africa, to initiate antidepressant medication as contained in the new South African Mental Health Policy Framework and Acton Plan (2023-2030) [52], is underlined.
Regarding maintenance, the establishment of a learning collaborative with the researchers and provincial policy makers provided the platform for facilitating the adoption of the majority of the tailored implementation strategies into policy.This was central to strengthening the acceptability of the implementation package by the providers in the district, as well as creating an enabling policy environment for sustainability and scale-up of components of the implementation package to the rest of the province of KZN.To this end, the learning collaborative was expanded during the COVID-19 pandemic to include all the mental health coordinators across all 11 districts in the KZN province.Working incrementally and starting with screening, using routine data and continuous quality improvement small tests of change, SMhINT has supported the KZN DoH to introduce and embed the BMH into all districts, with a view to using the same approach for the other tools along the cascade of care.The work of SMhINT has also been integrated into a broader initiative to strengthen comprehensive integrated primary health care in the KZN province to facilitate maintenance and scale up.

Limitations
The lack of engagement of people with lived experience within the learning collaborative and the focus on inputs and outcomes without also looking at quality of services from service user perspectives are recognized.The nurse diagnosis and referral checklist may have primed nurses to make a diagnosis thus inflating the percentage of service user participants who screened positive for depressive symptoms who were diagnosed.The observational design poses a limitation for evaluation of effectiveness and causal inference.A randomized control trial design was precluded by the adoption of a learning collaborative strategy necessary to create an enabling policy environment, with policy changes applied to all districts across the province, including the target district where the research was conducted.The restriction of focus on the PHC clinic facility level of care (with little attention to community care) was also a limitation.Although, as indicated, the CMED has since been developed using a SMhINT supplementary grant to provide an educational tool for CHWs to increase demand for services through psychoeducation, screening and linkage to care at a community level.

Conclusion
Integrated depression care within routine PHC clinic services can be successfully implemented in resource-constrained settings through integrating depression services into routine activities for other medical conditions along the care cascade.Establishing a learning collaborative with PLOS GLOBAL PUBLIC HEALTH policy makers, researchers and implementers is key to creating an enabling policy environment that ensures that successful strategies are mandated, including tools and revisions to health care worker roles and responsibilities.A validated, mandated mental health screening tool, embedded in the system using on-site educational outreach and technical support visits together with small tests of change, emerged as important for assisting Professional Nurses to diagnosis and refer service users with depression in this resource-constrained real-world PHC service delivery context.Further research efforts are, however, required to narrow the treatment uptake gap and assess quality of care.To this end, research is needed to assess whether improved availability of on-site treatment for depression as well as improved population mental health literacy may assist to improve treatment uptake and quality.While adequate mental specialist resources will always be necessary for training, supervision and providing referral resources for complex severe mental health conditions, the notion that LMICs potentially have a wealth of human resources to draw on to narrow the treatment gap for common mental conditions is supported [53].

.
Lack of a validated standardized screening tool resulting in inadequate and inconsistent screening A standardized screening tool was developed and validated to ensure quality of screening (develop and implement tools for quality monitoring) [Brief Mental Health (BMH) screening tool] [38].The use of the tool was mandated through adoption into policy by the KZN DoH.A training manual (training material) and standard operating procedure (develop and implement tools for quality monitoring) for use of the tool was co-developed with the KZN DoH.It was initially used alongside screening for other conditions within PHC facilities in 'vital signs' rooms by Enrolled Nurses where service users are triaged clinically before consultations, but later also extended for use by Professional Nurses.Training of Operational Managers, Professional Nurses and Enrolled Nurses in each PHC clinic was delivered through educational outreach visits that also included small tests of change provided by the Implementation:

Table 1 .
(Continued) Kemp et al. 2021b-sample of cohort participants who screened positive for depressive symptoms prior to assessment by a nurse, 50.5% were diagnosed with depression using APC.Of these, 36.5% were referred, translating into 18.4% of the original cohort subsample that screened positive for depressive symptoms at baseline.Of those referred, 23.7% received at least one counselling session, meaning that of the original sub-sample of service users screening positive for depressive symptoms, only 4.4% received at least one counselling session.SeeKemp et al. 2021for more details

to which the intervention was implemented with consistency and fidelity along the cascade of care, adaptations made during the study, and cost)
District Mental Health coordinator and S-MhINT project implementation coordinator (technical assistance) (See more details in TIDieR description in the online Supporting Information, S2 Appendix).